Description
TM 9-3025 Technical Manual - 155mm M46/T80 Gun, 8-Inch M47/T89 Howitzer and M86/T58 Mount - September 1957
Item Overview
TM 9-3025 is a September 1957 Army technical manual for the 155mm M46/T80 gun, 8-inch M47/T89 howitzer, and shared M86/T58 gun and howitzer mount. Written for ordnance field and depot maintenance, this publication documents the armament fitted to two early Cold War self-propelled artillery systems. It brings the cannons and their common mounting equipment together in one reference.
Identification and Features
The following details identify this publication and its equipment coverage:
- Publication number: TM 9-3025
- Publication date: September 1957
- Issuing authority: Department of the Army
- Maintenance level: Ordnance field and depot maintenance
- 155mm gun: M46, development designation T80
- 8-inch howitzer: M47, development designation T89
- Gun and howitzer mount: M86, development designation T58
- Documented vehicle applications: M53 self-propelled gun and M55 self-propelled howitzer
Function and Manual Contents
This manual addresses maintenance support for the covered gun, howitzer, and mount assemblies. Its scope centers on the armament and supporting mount at the field and depot repair levels. For researchers, that focus helps connect the cannon itself with the cradle and recoil equipment that supported it inside the vehicle. It is useful for studying how the complete armament installation was maintained.
Publication History
Published in September 1957, TM 9-3025 belongs to the Army's postwar technical literature for heavy mobile artillery. Its title preserves both the equipment's development designations and its standardized service names. The September 1957 edition is also recorded in the Springfield Armory archival catalog, documenting its place in the Army's maintenance publication series.
Documented End-Item Application
The 155mm M46 gun was the main armament of the M53 self-propelled gun. The 8-inch M47 howitzer armed the related M55 self-propelled howitzer. Both installations used the M86 mount, which supported two different cannon types within closely related tracked vehicles.
Equipment History
The covered equipment belongs to the 1950s development of enclosed American self-propelled artillery. Heavy cannon installations had to combine recoil control, ammunition handling, and space for the crew within a mobile fighting compartment. The M46, M47, and M86 formed part of that engineering effort, bringing established heavy artillery roles into protected tracked installations.
155mm M46/T80 Gun History and Background
Developed under the T80 designation, the M46 continued the American long-range 155mm gun role associated with the earlier Long Tom family. Army ammunition references describe its tube as similar to that of the towed M2 gun and document shared ammunition between the two weapons. This connection links the M46 to an established field gun tradition while placing it in a newer self-propelled installation. Its cannon assembly included the tube and breech ring, breech mechanism, firing lock, and breechblock counterbalance.
8-Inch M47/T89 Howitzer History and Background
The M47 developed as the T89 and carried the heavy 8-inch, or 203mm, howitzer role into the related artillery installation. Its larger projectiles suited heavy bombardment work. The weapon retained ties to the ammunition family used by the earlier M2 and M2A1 8-inch howitzers. Heavy ammunition also shaped its support equipment: the M55 installation included a dedicated ammunition hoist. These features give the M47 a distinct design and support history within the paired artillery program.
M86/T58 Mount History and Background
Developed as the T58, the M86 was a common mount design for the 155mm gun and 8-inch howitzer. Its cradle supported and aligned the cannon tube. A recoil mechanism using hydraulic fluid and springs controlled the weapon's movement during firing, with recoil cylinders and replenisher assemblies forming key parts of the system. The shared mount linked the two cannon programs through common supporting equipment.
Parent Weapon-System Background
The M53 and M55 were closely related tracked artillery vehicles developed during the early Cold War. Their chassis drew on Patton tank components, with the engine and transmission at the front and an enclosed fighting compartment toward the rear. This arrangement combined heavy artillery firepower with crew protection and tracked mobility, supporting formations operating beyond improved roads.
History of Use
The covered armament saw service beyond the period when this manual was published. Both the M53 and M55 served with Marine force artillery in Vietnam, carrying the M46 gun and M47 howitzer into combat use. Official Marine Corps history records the replacement of the M55 by the M110 during 1967. Their service connects this maintenance reference with the transition from early Cold War artillery to the next generation of self-propelled weapons.
Ideal For
This manual suits collections focused on heavy artillery design, military maintenance, and Cold War equipment. Its combined coverage is especially useful for studying the differences between the two cannons and the common mount that supported them.
- Army technical manual collectors
- M46 gun and M47 howitzer researchers
- M86 mount and recoil system historians
- M53 and M55 restoration archives
- Military museums and reference libraries
Approx length 6", Approx width 9", Approx height .5", Approx weight 1lbs.
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